The two leaders agreed on the importance of full cooperation so that the investigation proceeds smoothly, said a Turkish presidential source, who spoke on condition of anonymity due to restrictions on talking to the media.

They further agreed on the exchange of information about the latest developments.

Khashoggi, a Saudi journalist and columnist for The Washington Post, has gone missing since he entered the Saudi Consulate in Istanbul on Oct. 2.

On the day of his disappearance, 15 other Saudis, including several officials, arrived in Istanbul on two planes and visited the consulate while Khashoggi was still inside, according to Turkish police sources. All of the identified individuals have since left Turkey.

On Wednesday, crime scene investigation units arrived at the official residence of Saudi Consul General Mohammad al-Otaibi around 4.40 p.m. local time (1340GMT). Al-Otaibi had left Turkey for Riyadh on Tuesday.

Officials from a joint Turkish-Saudi team completed an investigation into the case early Thursday after searching the residence as well as the Saudi consulate in Istanbul.